The present invention relates to devices which are used to connect an endotracheal tube to the source of air or other gas, such as anesthetic gas, which the medical practitioner desires to introduce into a patient's respiratory system. Specifically, this invention pertains to an improved construction of the patient end of the connector, i.e. the end which fits into the gas-source end of the endotracheal tube.
The endotracheal tube connectors currently in use all share a common configuration for the patient end. This configuration consists basically of a cylindrical barrel whose inside diameter is the same as the inside diameter of the tube in order to ensure an airtight fit, maximum gas flow, and minimum turbulence. Typically, the outside diameter of the outer cylindrical barrel is tapered at the patient end to facilitate insertion into the tube.
Several problems with this configuration have arisen in practice. The requirement that the inside diameter of the connector be equal to that of the tube results in the outside diameter of the connector being greater than the inside diameter of the tube. This results in considerable difficulty in inserting the connector into the tube, even when the barrel diameter is reduced on a taper. This difficulty is increased in practice because the physician normally cuts the endotracheal tube to the desired length during the medical procedure, and the cutting operation often squeezes the tube, resulting in a tube end with an oval cross-sectional shape. Also, the walls of endotracheal tubes very often contain a cuff inflation lumen. This structure also results in a non-circular tube cross section which contributes to the difficulty of inserting the prior art connectors. Ease of assembly is critical in the medical application of the endotracheal tube, as the time spent inserting the connector may mean the difference between the life and the death of the patient.
Also, the standard connector, as previously described, requires significant care for proper insertion. This is due to the fact that the reduced barrel diameter at the patient end results in a very thin wall section which is prone to damage in the process of insertion. Such damage may result in an obstruction which diminishes gas flow and/or increases turbulence and may make catheter insertion more difficult, or require the use of an undersize catheter. Minute pieces of the edge of the connector may also be broken off, resulting in the inhalation of foreign particles by the patient. The care required for insertion also adds measurably to the time required for assembling the endotracheal apparatus.